This is a front-end for the Online Encyclopedia of Integer Sequences, made by Christian Perfect. The idea is to provide OEIS entries in non-ancient HTML, and then to think about how they're presented visually. The source code is on GitHub.
| n | a(n) |
|---|---|
| 1 | 1 |
| 2 | 1 |
| 3 | 0 |
| 4 | 4 |
| 5 | 5 |
| 6 | 96 |
| 7 | 427 |
| 8 | 6448 |
| 9 | 56961 |
| 10 | 892720 |
| 11 | 11905091 |
| 12 | 211153944 |
| 13 | 3692964145 |
| 14 | 75701219608 |
| 15 | 1613086090995 |
| 16 | 38084386700896 |
| 17 | 949168254452993 |
| 18 | 25524123909350112 |
| 19 | 725717102391257347 |
| 20 | 21955114496683796680 |